非平衡分子动力学

[]1001246X(2007)04046304[]2006-03-03;[]2006-08-09[](No50606018)[](1975-),,,,,.曹炳阳(,,100084)[](NEMD),,Fourier,MllerPlathe(RNEMD),,NEMD,.RNEMD.[];;[]TK124;O5513[]A0,[1].:(EMD)(NEMD).EMD,,GreenKubo,=13VkBT2!∀0#J(t)J(0)∃dt,(1)V,kBBoltzmann,T,t,J.,EMD[2].NEMD,Fourier,J=-T.(2),NEMD,(PBC),[3-5].NEMD,,,,.NEMDEMD,.MllerPlathe(RNEMD)[6,7],,,NEMD.NEMD,Fourier.NEMD,,,Fourier,,[8].,NEMD,,,.,RNEMD.24420077CHINESEJOURNALOFCOMPUTATIONALPHYSICSVol.24,No.4Jul.,200711.,,.,T=qv2(x+Lx4)2-qvL2x32+T0,-Lx2%x%0,-qv2(x-Lx4)2+qvL2x32+T0,0x%Lx2,(3)qv,,T0,Lx(x).(3),NEMD1Fig1Schematicofthesimulationmethodbasedonuniforminternalheatsource,.MllerPlathe[6],x,,,.,.qv=&t,transferm2(v2c-v2h)t(Lx2)LyLz,(4)t,m,LyLz,vcvh.,RNEMD,.2,RNEMD,,[6].Lennard_Jonesu(r)=4(!r)12-(!r)6,(5)r,=1653∋10-21J,!=3405∋10-10J.,!m=6633∋10-26kg,:kB=1198K;1!3=253∋1028m-3;∀=(m!2)12=215∋10-12s;kB(∀!)=188∋10-2W((mK)-1.*,[6].2940,L*x∋L*y∋L*z=2514∋1173∋1173.:T*=07;#*=085.LeapfrogVerlet[9],t*=0005.,,,T=#&atomimiv2i∃3(N-1),(6)N.W.46424(LinkedCellList).100000,100000.3312Fig2Temperatureprofiles2.RNEMD,.RNEMD,,.,,RNEMD,W=10,RNEMD053~083,064~077,W=200,RNEMD0690~0712,0695~0707.,RNEMD.32,(3).,RNEMD,.RNEMD,.W=10,RNEMD081~089,083~087,W=200,RNEMD0846~0853,0848~0852.,,RNEMD.334.,10%.RNEMD,,RNEMD,,,RNEMD.,RNEMD,,.3Fig3Densityprofiles4Fig4Thermalconductivities4654:4,.,MllerPlatheRNEMD,NEMD,.:MllerPlathe[7].[][1]EvansDJ,MorrisGP.Statisticalmechanicsofnonequilibriumliquids[M].London:Academic,1990.[2]SchellingPK,PhillpotSR,KeblinskiP.Comparisonofatomiclevelsimulationmethodsforcomputingthermalconductivity[J].PhysicalReviewB,2002,65:144306-1-12.[3],,.[J].,2001,22(2):195-198.[4],,,.[J].,2000,45(19):2113-2117.[5],,.[J].E,2003,33(5):429-434.[6]Mller_PlatheF.Asimplenonequilibriummoleculardynamicsmethodforcalculatingthethermalconductivity[J].JournalofChemicalPhysics,1997,106(14):6082-6085.[7]ZhangMM,LussettiE,SouzaLES,Mller_PlatheF.Thermalconductivitiesofmolecularliquidsbyreversenonequilibriummoleculardynamics[J].JournalofChemicalPhysicsB,2005,109:15060-15067.[8]ChantrenneP,BarratJL.Finitesizeeffectindeterminationofthermalconductivities:comparingmoleculardynamicsresultswithsimplemodels[J].ASMEJournalofHeatTransfer,2004,126:577-585[9]AllenMP,TildesleyDJ.Computersimulationofliquids[M].Oxford:OxfordScience,1987.[10]LideDR,ed.Handbookofchemistryandphysics[M].BocaRaton:ChemicalRubber,1993.ANonequilibriumMolecularDynamicsMethodforThermalConductivitySimulationCAOBingyang(DepartmentofEngineeringMechanics,KeyLaboratoryforThermalScienceandPowerEngineeringofMinistryofEducation,TsinghuaUniversity,Beijing100084,China)Abstract:Anonequilibriummoleculardynamics(NEMD)methodbasedonconstructionofuniforminternalheatsourceforsimulatingthermalconductivityisputforward.ThemethodholdsenergyandmomentumconservationsandshowsrapidconvergencecomparabletothereversedNEMD(RNEMD)method.ItovercomesthelocalthermodynamicnonequilibriumproblemofhotcoldsourceregimesintraditionalNEMDschemes.ComparedwiththeRNEMDmethod,themethodmaycausesmallertemperaturedifferenceanddensityinhomogeneityinthesimulatedmoleculesystem.ThemethodisusedtosimulatethermalconductivityofliquidargonandiscomparedwiththeRNEMDmethod.Keywords:moleculardynamicssimulation;thermalconductivity;uniforminternalheatsourceReceiveddate:2006-03-03;Reviseddate:2006-08-0946624